This invention relates to a tilt device for an outboard drive and more particularly to an improved arrangement for attaching an outboard drive such as the outboard motor or the outboard drive section of an inboard/outboard drive to the hull of an associated watercraft.
Normally outboard drives and specifically the attachment thereof to the transom of an associated watercraft are comprised of a number of components that are connected together by fasteners. Generally, these elements comprise a pair of clamping brackets that are affixed to the transom and define pivot axes for a tilt shaft. This tilt shaft is provided to journal the swivel bracket of the outboard drive for pivotal movement to the hull so that the trim angle of the outboard drive can be adjusted and also so that the outboard drive can be titled up out of the water.
These clamping brackets are affixed to a separate member that is comprised of a cylinder holding member. This cylinder holding member provides a mounting for a tilt cylinder assembly which is pivotally connected at one end to the cylinder holding member. The piston rod of this tilt cylinder is pivotally connected to the swivel bracket so that when the tilt cylinder is operated, the swivel bracket will be tilted up to raise the propulsion unit of the outboard drive out of the water.
In addition, a pair of trim cylinders is provided which are normally disposed on opposite sides of the tilt cylinder and which have piston rods that engage the swivel bracket to adjust the trim position during the operation. This adjustment is normally in the range of about twenty degrees (20°) while the tilt movement is much greater, such as about seventy degrees (70°).
The cylinder holding member also mounts a reversible electric motor and hydraulic pump as well as the hydraulic circuitry for operating the tilt cylinder and trim cylinder.
In addition to all of these functions, the tilt device further includes a pair of spaced apart abutments normally formed on the clamping brackets that engage opposite sides of the swivel bracket of the outboard drive so as to guide its movement when trimmed and tilted and also to take side thrusts. Hence, the components experience high loads and because they are formed by a number of separate pieces, each piece becomes rather heavy and complicated in addition, time is required to assemble these components and basically the weight becomes quite excessive and the cost is increased.
The type of prior art construction described may be best understood by reference to FIG. 1 which is a perspective view taken from the rear of a conventional prior art type of a tilt device for an outboard drive. The tilt device assembly is indicated generally by the reference numeral 11.
This assembly is comprised of a pair of transversely spaced apart clamping brackets, indicated generally by the reference numeral 12, each of which has a flange portion 13 that is adapted to be abuttingly engaged with a watercraft hull and primarily the transom thereof. These portions 13 are provided with a series of vertically spaced apertures 14 and a lower vertically extending aperture 15 that are adapted to receive threaded fasteners for fixing the clamping brackets 12 to the watercraft hull.
Extending rearwardly from these flanges 13 are wing-like portions 16, the upper ends of which define trunions or bearings 17 that are adapted to receive a tilt pin which, in turn, pivotally supports the swivel bracket of the outboard drive.
Affixed to these clamping brackets 12 is a cylinder holding member, indicated generally by the reference numeral 18. This cylinder holding member 18 is an assembly that provides at the lower end thereof a pivotal support for a trunion 19 of a tilt cylinder, indicated generally by the reference numeral 21. This tilt cylinder 21 is a hydraulically operated device and has an outwardly extending piston rod 22 that has a trunion 23 at its upper end for providing a pivotal connection to the swivel bracket of the outboard drive. When the piston rod is extended from the position shown in FIG. 1, the outboard drive will be tilted up to an out-of the water position.
In addition, a pair of trim cylinders, each of which is indicated generally by the reference numeral 24 is supported on opposite sides of the tilt cylinder 21 by the cylinder holding member 18. These trim cylinders are received in cylindrical bosses 25 formed in the cylinder holding member 18. Each trim cylinder 24 has a trim piston 26 that is abuttingly engaged with the swivel bracket for adjusting the trim position thereof.
Mounted on the cylinder holding member 18 also is the hydraulic control system and operating system for tilt cylinder 21 and trim cylinders 24. This includes a reversible electric motor 27 that drives a reversible hydraulic pump that receives fluid from a fluid reservoir 28. Fluid is circulated to the trim cylinder 24 and tilt cylinder 21 through suitable hydraulic circuitry which may include external conduits 29 and 31 as well as conduits formed internally in the assemblage.
The cylinder holding member 18 is affixed to the clamping brackets 12 by a plurality of threaded fasteners 32 which, in the illustrated prior art embodiment, are comprised of four at each side.
In order to hold the swivel bracket of the outboard drive against traverse movement during its tilt and trim operation, the clamping brackets are formed with abutment or guide surfaces 33 which embrace opposite sides of the swivel bracket and which hold it. Since the loads encountered are quite high, the entire assemblage tends to become heavy and is made by a number of castings which must be fixed to each other and thus, because of the separate assemblage, each component must be relatively heavy and the overall construction and its assemblage becomes bulky, heavy and expensive.
It is, therefore, a principal object to this invention to provide an improved and simplified tilt device for a marine outboard drive.
It is a further object to this invention to provide an improved tilt device for a marine outboard drive that is simple and lightweight in construction and nevertheless able to absorb the large loads that are placed upon it.